Analytical devices utilizing measuring gases are known in the art as useful for the measurement of process gases and combustion products. For certain analytical measurements it is desirable to maintain a constant dew point for the measuring gas to accurately calibrate the analytical device and to eliminate the effect of water vapor on the analytical measurement results. Measuring gas analytical devices capable of maintaining a constant dew point for the measuring of gases usually comprise a means for the condensation and removal of water vapor from the measuring gas. This water vapor condensation and removal means typically comprises a heat exchanger for the cooling of the measuring gas and condensation of the water vapor, that also has a condensation separator for removal of the condensed water vapor from the measuring gas.
A typical heat exchanger and condensation separator for the removal of water vapor from a measuring gas is disclosed in German Pat. No. 31 11 415 A1. The heat exchanger of this device essentially consists of a pipeline for transporting the measuring gas wrapped around a collector for the cooled gas from which the water vapor condensate precipitates, which is immersed in a sealed refrigerant bath. This design has several drawbacks. Typical refrigerants attack most synthetic plastic materials; therefore, the choice is limited for the parts of the device, most of which are in contact with the refrigerant, especially the measuring gas line, which is immersed in the refrigerant, and the heat exchanger housing, which holds the refrigerant.
An additional problem is presented in the selection of materials for the measuring gas line because the materials for this line must also be acid resistant. Additionally, in many applications, the refrigerant is supplied at a higher pressure than the measuring gas, e.g., between about 2 to 3 bars versus between about 0.1 to 0.5 bars, and accordingly, the other parts of the device are also limited to materials capable of withstanding the higher refrigerant pressures. Consequently, measuring gas cooling devices have in the past been limited to being manufactured from materials such as specialty steels, which are undesirable because they are expensive, and glass, which is undesirable because it is fragile.
Cooling devices for the removal of water vapor from measuring gases are desired that can be manufactured from durable, inexpensive materials which resist attack from substances to which they are exposed. Therefore, it is an object of the invention to provide a measuring gas cooling device with reduced production costs by manufacturing the heat exchanger for the device with parts made from durable, inexpensive materials.
It is a further object of the invention to provide a measuring gas cooling device heat exchanger with parts made from durable, inexpensive materials by containing the refrigerant in a refrigerant line so that the other parts of the device need not be resistant to attack from the refrigerant or withstand the refrigerant pressure.
It is an object of the invention to provide a measuring gas cooling device in which the measuring gas line and heat exchanger housing, or container, are made from durable, inexpensive materials by containing the refrigerant in a refrigerant line so that the measuring gas line need be resistant to attack only from the measuring gas and, along with the heat exchanger container, need not be resistant to attack from the refrigerant or withstand refrigerant pressures, if higher.
It is an object of the invention to provide a measuring gas cooling device heat exchanger with a container that is transparent to permit monitoring of the interior of the device for maintenance and other purposes by containing the refrigerant in a line that permits the refrigerant container to be manufactured from durable, transparent material that need not withstand refrigerant pressure or attack.
The listing of objectives provided herein or of features of the inventions is not intended to be exhaustive but merely illustrative.
Other objects will become apparent to one of average skill in the art in the further description of the invention.